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0. S. GARRETSON. METHOD OF AND APPARATUS FOR MATTE 0R PYRITIG SMELTING.No.'596,99l.

Patented Jan. 11, 1898.

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O. S. GARRETSON. METHOD OF AND APPARATUS FOR MATTE 0R PYRITIG SMELTING.

No.- 596,991. Patented Jan.11,1898.

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nvvtltldlteoani UNITED STATES PATENT @rrron.

OLIVER S. GARRETSON, OF BUFFALO, NEXV YORK.

METHOD OF AND APPARATUS FOR MATTE OR PYRlTlC SMELTING.

SPECIFICATION forming part of Letters Patent No. 596,991 dated January11, 1898.

l Application filed November 7, 1896. Serial No. 611,338. (No model.)

To aZZ whom zit may concern:

Be it known that I, OLIVER S. GARRETSON, a citizen of the United States,residing at Buffalo, in the county of Erie and State of New York, haveinvented a new and useful Improvement in Methods of and Apparatus forMatte or Pyritic Smelting, of which the following is a specification.

This invention relates to that class of metallurgical operations andfurnaces which are employed in matte and pyritic smelting, and has forits object to treat the ore in a furnace in such manner that the ore issmelted to a matte in one part of the furnace and the matte is convertedor bessemerized in another part of the furnace, whereby metal orenriched matte, as the case may be, and practically clean slag areproduced by a simple and continuous operation, as will be hereinafterfully set forth.

In the accompanying drawings, consisting of two sheets, Figure 1 is alongitudinal vertical section of a furnace embodying my improvements andby which my improved method can be practiced. Fig. 2 is a horizontalcross-section in line 2 2, Fig. 1. Fig. 3 is a fragmentary longitudinalvertical section of the lower portion of the furnace on an enlargedscale. Fig. 4 is a diagram illustrating the flow of the molten materialin the furnace. Fig. 5 is a fragmentary cross-section of the top of thefurnace at right angles to Fig. 1 on an enlarged scale.

Like letters of reference refer to like parts in the several figures.

A represents the furnace, and B the forehearth or settling-well arrangedat one end of the furnace and communicating therewith by a passage 1).The furnace is preferably made long and narrow in horizontalcross-section, the forehearth being arranged at one of the narrow ends.The bottom 0 of the forehearth is practically on a level with the bottomof the passage 1) or slopes slightly toward said passage, so that anymatte or other molten metallic compounds which settle to the bottom ofthe forehearth flow back into the furnace.

o is the slag'outlet of the forehearth,whieh outlet is arranged somewhathigher than the passage 5. p p

The portion D of the furnace, which is near- F represents a row oftwyers which are constructed and arranged in any suitable mannor, so asto deliver a blast suitable for smelting into the smelting-zone of thefurnace, whichlies above the slag-level. This blast is preferably heatedby any suitable heating apparatus; but I prefer for that purpose thehot-blast apparatus which forms the subject matter of my application forLetters Patent filed October 29, 1896, Serial No. 610,403. In thishot-blast apparatus the blast is heated by the discharged molten slag ina conduit Gr, through which the slag is conducted by an endless carrier9. From this heating-conduit G the blast passes to the twyers throughtwo conduits G, arranged on opposite sides of the furnace and providedwith valves g for regulating or shutting off the blast.

H represents a row of twyers which are arranged in the converting orbessemerizing portion of the furnace at such a height that they'delivera blast suitable for converting or bessemerizing the matte in the zonewhich is occupied by the matte above the depressed portion 6 of thebottom of the furnace. This zone lies above the zone which is occupiedby the metal upon the depressed bottom and below the slag zone. Thepressure of this converting or bessemerizing blast is higher than thatof the smeltingblast in order to enable the converting-blast topenetrate the molten matte and may range from four to five or morepounds per square inch, while the smelting blast may range from one-halfto one and one-half pounds. The converting-blast need not be heated andmay be supplied to the twyers H by flexible pipes 71 from any suitableconduit. These converting-twyers H are preferably double, while thesmeltingtwyers may be single, as shown.

The top portion of the furnace is constructed in any suitable orwell-known manner for feeding the ore to the furnace and for permit tingthe escape of the gases through the uptakes Ifor instance, bypivoteddoors I, as shown in Fig. 5.

In practicing my invention the iron or copper sulfid ore, mixed with asuitable fiux,consisting mainly of silica-4'01 instance, quartz,diorite, or the like-is charged into the furnace at suitable intervalsin such a way that the furnace is kept fairly filled with ore and flux.7 In starting the furnace: a suitable amount of fuel is used, but whenthe operation is fully established the fuel may be entirely omitted, ornearly so, as the percentage of combustible ingredients in the ore maywarrant, As the ore is being smelted down a matte is formed. That partof the matte which collects on the depressed portion of thefurnace-bottom is converted or bessemerized, so that the metalisprecipitated and collects on the depressed bottom. The iron oxid whichis formed or liberated in forming the matte and in converting orbessemerizing the same combines with the silica to form a silicate,which flows freely as a liquid slag in the 'direction of the arrows 1,Fig. 4, from the bessemerizing portion E of the furnace toward thepassage 1 which leads from the furnace to the forehearth. In flowing tothe forehearth this liquid slag is compelled to flow through thematte-forming portion D of the furnace, where the raw ore and poor mattepredominate. The sulfur, which is there in excess, combines with anyfree metalsor oxids which may be carried by the slag and converts thesame into matte, whereby the copper and other values carried by the slagare returned to the matte. The latter flows toward the depressed portione of the bottom of the furnace, as indicated by the arrow 2, Fig. 4, andis there again subjected to the bessemerizingblast. In this manner acirculation is maintained in the molten material in the furnace. Amolten sulfur compound or matte is constantly formed in the portion ofthe furnace nearest the forehearth and over the elevated portion of thebottom. This comparatively poor matte flows constantly along the bottomof the furnace toward the opposite end thereof and becomes graduallyricher by the burning out of the sulfur, iron, and other combustibleingredients. The rich matte is constantly converted or bessemerized inthat portion of the furnace which lies over the depressed portion of thebottom. A correspondingly rich slag is constantly formed in theconverting portion of the furnace, which slag flows in the oppositedirection or from the bessemerizing end to the matte-forming end andpasses through the matte-forming portion before escaping to theforehearth, and the values contained in the slag are exposed to theaction of the predominating sulfur and poor matte in the matte-formingportion and are thereby intercepted and returned, whereby the escape ofValues with the slag is to a large extent prevented. In order to promotethis action of the molten materials, the matte-forming portion of thestack-furnace is preferably charged with proportionately more ore andthe bessemerizing portion of the stack with proportionately more flux,so that the raw ore and poor matte preponderate in the matte-formin gportion and the flux in the bessemerizing portion. If the ores which arebeing treated differ in the percentage'of sulfuror othercombustibleingredients, the ore containing most sulfur is used in the matte-formingportion.

The precipitated metal which collects on the depressed portion of thefurnace-bottom is drawn ofi from time to time through a suitabletap-hole 76.

Such metallic compounds as escape into the forehearth and settle thereflow back into the furnace through the passage 1).

The slag-outlet c of the forehearth is arranged higher than the passageZ). The blastpressure in the furnace is sufficient to drive the slag tothis outlet, through which it passes to the slag-inlet Zof the hot-blastapparatus,

if the latter is used. This pressure is maintained in the furnace, as iswell known, because the stackof the furnace is filled with a column ofore and fuel through which the blast must force its way in order toescape. If necessary, the stack of the forehearth may be kept filledwith charcoal, so that the slag is filteredthrough. the charcoal beforeescaping from the forehearth, whereby a further portion of the valuescontained in the slag is filtered out or reduced. The forehearth may beprovided with twyers m for'supplying air to burn a part of the charcoalsufficient to maintain the heat which is necessary to keep the slagsufficiently fluid. When such a heating of the forehearth is necessary,the stack of the forehearth is preferably provided with an escape-pipe Nfor the products of combustion, which pipe connects with the forehearthimmediately above its slag-outlet, while the feed-hopper O at the top ofthe stack of the forehearth is provided with a movable cover or bell P.This permits the charcoal to be burned in the forehearth at the bottomof the fuel-column in the manner of a base-burner.

The herein-described method and apparatus are applicable to the variousores for which matte or pyritic smelting is suitable-for instance,copper and iron pyrites, sulfids, arsenical ores, and others. Theprocess pro- Y duces in a simple, direct, and continuous manner ametallic alloy or a rich matte and substantially clean slag.

I claim as my invention- 1. The herein-d escribed method of matte orpyritic smelting which consists in conducting the operations ofproducing molten matte and converting or bessemerizing the same side byside, maintaining a flow of matte from the matte-forming region to theconnecting or bessemerizing region, forming a fluid slag by the additionof him in the converting or bessemerizing region, and compelling suchslag to flow through the matte-forming region on its way to theslag-outlet, thereby subjecting the slag to the action of the sulfur andsulfids in the matte-formin g region, whereby the values contained inthe slag are intercepted and returned to the matte, substantially as setforth.

2. The herein-described method of matte or pyritic smelting whichconsists in conducting the operations of producing molten matte andconverting or bessemerizing the same side by side in the same furnaceand charging the matte-forming region with a preponderance of ore andthe converting or bessemerizin g region with a preponderance of flux,substantially as set forth.

3, A smelting and converting furnace havin g its bottom provided with adepressed portion near one end of the furnace, a device for supplying aconverting or bessemerizing blast arranged over the depressed portion ofthe bottom, and a slag-outlet arranged at or near the opposite end ofthe furnace, above the elevated portion of the bottom, substantially asset forth.

a. A smelting and converting furnace havin g its bottom provided with adepressed portion near one end of the furnace, a stack arranged over theelevated and the depressed portions of the bottom, a device forsupplying a converting or bessemerizing blast arranged over thedepressed portion of the bottom, a device for supplying a smelting-blastar ranged over the elevated portion of the bottom, and a slag-outletarranged at or near the opposite end of the furnace above the ele-'vated portion of the bottom, substantially as set forth.

5. The combination of a smelting and converting furnace having itsbottom provided with a depressed portion near one end of the furnace, adevice for supplying a converting or bessemerizing blast arranged overthe depressed portion of the bottom, a device for supplying asmelting-blast arranged over the elevated portion of the bottom, and aslag outlet arranged at or near the opposite end of the furnace abovethe elevated portion of the bottom, of a forehearth communicating withsaid slag-outlet and having its bottom arranged practically on a levelwith the ele vated portion of the bottom of the furnace, substantiallyas set forth.

6. The combination with a smelting-furnace, of a forehearthcommunicating with the slag-outlet of said furnace and having aslagoutlet, a stack which is independent of said furnace and extendsupwardly from said slagoutlet and is adapted toholda column of fuel, anda conduit for the escape of the products of combustion which is separatefrom the smelting-furnace and from said stack and connected with thelower portion of said stack, substantially as set forth.

lVitness my hand this 6th day of November, 1896.

OLIVER S. GARRETSON.

lVitnesses:

JNo. J. BONNER, KATHRYN ELMORE.

